Adolpii frank



ADOLPH FRANK, OF OHARLOTTENBURG, AND NIKODEM OARO, OF BERLIN,

- GERMANY.

PROCESS OF MAKING CYANIDS.

SPECIFICATION forming part of Letters Patent No. 623,709, dated April 25, 1899.

Application filed December 3,1897. Serial No. 660.670. (No specimens.)

T at whom it may concern:

Be it known that we, ADOLPH FRANK, of Charlottenburg, and NIKODEM OARO, of Berlin, Germany, have invented certain new and useful Improvements in a Process for the Preparation of Cyanogen Compounds, (for which Letters Patent have been obtained in Germany, No. 92,587, dated December 1 1895, and No. 95,660, dated January 1, 1896; in Bel- IO gium, No. 119,222, dated January 4, 1896; in France, No. 249,539, dated January 4, 1896; in Austria, No.47/1,909, dated May 22, 1897; in Cape Colony, No. 116, F01. 1149, dated April 4, 1896; in Orange Free State, No. 93,

Book A, No. 185, dated October 29, 1896; in South African Republic, No. 1,083, dated March 23, 1896, and in Sweden, No. 7,422, dated January 20, 1896;) and we do hereby declare the following to be a full, clear, and

exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

In Letters Patent of the United States granted to us September 21, 1897, No. 590,217,

we have described a process of producing cyanogen combinations from carbids of a suitable metal, as one of the alkalies, by subjecting the heated carbid to the action of nitrogen in presence of moisture, whereby the nitrogen is absorbed under formation of cyanide. Thus if barium carbid, for instance, is used, the reactions take place in accordance with the following equations:

1. BaC,-i-N, =Ba(ON) A portion of the carbid is, however, decomposed and converted into an oxid.

2. BaO,-l-H,O:H,O,+Ba0

Then the acetylene formed combines in static nasccndt with nitrogen to form hydrocyanic acid.

The extent or degree of the first reaction is a moderate one only, the actual formation of cyanide taking place after the third reaction.

If dry nitrogen is passed over a chemicallypure carbid, there is little or no absorption, as has been determined by the experiments of Moissan,(0omptes Rendus, 1894, page 503,) while cyanogen is formed when the nitrogen is caused to react upon the carbid in presence of moisture, as above stated. lVe have since discovered that an excellent yield of cyanides can be obtained from carbids by the action of nitrogen alone2'. 6., in the absence of moisture in the form of steam or otherwise, which in the process described in our patent above referred to was deemed essential when the carbid contains an oxid of a metal even in very small proportion. If, for instance, nitrogen is caused to react upon a carbid either in the presence or absence of moisture, but in the presence of an oxid as such or in the form of its combinations 6. g., carbonate, sulphatenear1y the whole of the carbid is converted into cyanide, while, as stated, the nitrogen will not react upon a chemically-pure carbid unless moisture is present. 7

In our improved process nitrogen in any desired form can be used, free or boundas, for instance, air freed or partially freed from its oxygen, nitrous gas, or nitrogen bound to another substance, as ammonia or ammoni- 8o acal salts, or organic or inorganic solid substances in a dry or moist condition and capable of giving off nitrogen or organic or inorganic liquids capable of giving off nitrogen can be used. In either case cyanide will be formed in the presence of heat-i. 6., when the carbid is heated about to a red heat, as described in our patent hereinbefore referred to.

The oxid or the salt of a metal maybe mixed with the carbid, or a carbid may be manufac- 9o tured which is not chemically pure, but which contains a very small percentum. of an oxid or combination of oxids, as above mentioned. It has been said that only a small percentage of oxid is necessary, by which it is to be un- 5 derstood that it is in general only necessary to have a small percentage of the described oxid present, and practice has shown that from ten per cent. to twenty-five per cent. is sufficient; but it is evident that the carbid may contain as much as fifty per cent.

When gaseous nitrogen is used, the process is carried out as follows: The carbid containing an oxid or a salt of a metal is finely pulverized and is heated to a red heat in a suitable retort provided with gas supply and exhaust devices. The nitrogen or nitrogenous gas in a dry state or accompanied by moisture is allowed to flow slowly into a retort, and as soon as absorption ceases the contents are allowed to cool and are then worked up in the usual manner.

hen the nitrogen is used in a liquid formas, for instance, in the form of an organic nitrogeniferous combination, as pyridine or waste products resulting in the manufacture of pyridinethe nitrogenous liquid is first condensed by evaporation and the vapors of the condensed liquid are then brought into contact with the heated carbid in the manner above described.

\Vhen solid nitrogenous substances are used, as urea, ammoniacal salts, or the like, the process is preferably carried out in an ordinary furnace or in a muffle-furnace, into which the mixture of carbid with an oXid or a salt of a metal and with the nitrogenous substance are charged or into which the carbid mixture and the nitrogenous substance are charged in superposed layers, which upon being heated to a red heat will result in the formation of cyanide, the latter being then eliminated from the residuary material by lixiviation or byinereasing the temperature to or above the melting-point of the cyanide to melt the latter, thereby causing it to settle and collect in the furnace-hearth, from which it can be drawn in the usual manner.

Any suitable carbid can be usedas, for instance, a carbid of a metal of the alkalies or alkaline earths-and any suitable oxid, as such, in a combined stateas, for instance, an oxid of a metal of the alkalies or of the alkaline earths or of iron or carbonate or sulphate of such oxids.

If oxid of iron (as such or in a combined state) be present, the cyanides are obtained in the form of ferrocyanides or ferricyanides.

Having thus described our invention, what we claim as new therein, and desire to secure by Letters Patent, is

1. The process of producing cyanides from carbids, which consists in subjecting the carbid to the action of heat and of nitrogen in the presence of an oxid of a metal only, substantially as set forth.

2. The process which consists in heating a carbid mixed with an oxid of a metal and a substance capable of giving off nitrogen, substantiall y as set forth.

3. The process, which consists in mixing with a carbid an oXid of a metal and a substance capable of giving oil? nitrogen, heating the mixture to a temperature below the melting-point of the cyanide to be produced until absorption of nitrogen ceases, then raising the temperature to or about to the meltingpoint of such cyanide, substantially as and for the purpose set forth.

In testimony that we claim the foregoing as our invention we have signed our names in presence of two subscribing witnesses.

AD OLPlI FRANK. NIKODEM OARO.

lVitnesses:

MAX. C. STAEHLER, WOLDEMER HAUP'I. 

